COAL  IN  NORTHWESTERN  COLORADO  AND  NORTHEASTERN  UTAH.       293 
DETAILED   DESCRIPTION  OF  THE  COAL,  FIELDS. 
SCOPE  OF  TEXT  AND  MAPS  IN  PRESENT  REPORT. 
The  extent  and  areal  distribution  of  the  outcrops  of  the  geologic 
formations/  with  special  reference  to  those  containing  the  valuable 
coals,  are  represented  on  the  geologic  maps  (Pis.  XVI-XX).  These 
maps  are  arranged  to  suit  convenience  of  publication  and  descrip- 
tion, retaining  the  scale  of  4  miles  to  the  inch  which  was  used  in  the 
reports  on  adjacent  districts  and  which  is  also  that  of  the  Hayden 
and  King  maps  of  this  part  of  Colorado. 
^reeK^^ri/     ^^"C 
Q?' 
onlaming    workable  beds 
workable  beds 
\  •'  '  .   .'  \Areas  probably 
\  ■  .  .  ■    I  workable    coal 
Tig.  5.— Map  of  Colorado  and  northeastern  Utah  coal  fields,  showing  areas  represented  by  Pis. 
XVI-XX:  Western  part  of  Yampa  field  (PI.  XVI);  lower  White  River  field  north  of  the  base 
line  (PI.  XVII);  Douglas  Creek  district,  lower  White  River  field  south  of  the  base  line  (PL  XVIII); 
Vernal  field  (PI.  XIX) ;  Henrys  Fork  field  (PI.  XX). 
In  the  brief  space  of  this  preliminary  report  only  a  very  general 
description  of  the  conditions  in  the  several  fields  can  be  given  in  the 
text.  The  territory  examined  naturally  belongs  to  several  more  or 
less  distinct  fields,  as  shown  by  fig.  5.  These  fields  are  described  in 
the  following  pages.. 
WESTERN  PART  OF  THE  YAMPA  FIELD. 
DISTRICT    COVERED    IN    PRESENT    REPORT. 
The  examination  of  the  Yampa  field  in  the  former  work  in  that 
region  was  not  carried  on  in  much  detail  west  of  the  mouth  of  Williams 
Fork,  although  the  coal-bearing  rocks  of  the  Mesaverde  and  overlying 
